In the state of the art, a body part is already known that forms a bumper skin. The bumper skin has a face that is visible from outside the vehicle and it is defined by bottom and top transverse edges. The bumper skin is also defined by side edges. A portion of each side edge is connected to each fender of the vehicle and another portion defines at least a fraction of each wheel arch. These transverse and side edges may include portions that are rectilinear or curved, concave or convex, depending on the style of the bumper skin.
Once the bumper skin has been mounted on the vehicle, the top edge has two portions that are masked by members that are fitted to the vehicle, e.g. two head light assemblies. The portion of the top edge that is complementary to the two portions masked by the light units can be seen by the user of the vehicle, in particular when the motor vehicle is in a hood-open position.
In order to guarantee that the vehicle presents good appearance and good perceived quality, the top and bottom edges form rims that extend substantially in register with the visible face of the bumper skin to which they are connected. The rim formed by the top edge enables the vehicle to be given good finish, in particular when the vehicle hood is open, whereas the rim that is formed by the bottom edge generally serves to contribute to the style of the vehicle.
While the bumper skin is being painted, a plurality of bumper skins are arranged on a vertical support in a painting installation so that the bottom and top transverse edges of two successive parts are adjacent.
In order to paint each bumper skin completely, in particular its visible face and the rims formed by the edges, it is common practice to use paint-applicator robots that are suitable for moving along a three-dimensional path. Firstly, such robots are very expensive and very complex to control. Secondly, since the part is three-dimensional, the time required for applying paint is relatively long. Finally, the gaps between the skins on a given support need to be relatively wide to allow the robots to pass between the skins in order to apply paint to the rims formed by the edges. These gaps between the skins reduce the number of skins that can be placed on the support and thus reduce the throughput of the painting installation.